Elevator cab doors are typically mounted on a track via guide rollers, the track being secured to the cab. Door opening and closing motion of the door or doors is caused by an electric drive motor which is mounted on the cab. The drive motor is a reversible motor which drives one or two sets of articulated arms that are pivotally attached to the door or doors. These drives are relatively complex assemblages, and require a large number of components. These drives also create high levels of stress on the cab due to the long levers used to open and close the doors. The reaction forces created by flexing the levers tend to cause the drive motor to twist on the cab. This reactive twist occurs in both directions, and requires reinforced cab structure to stabilize the cab.